A new book claims smoking, drinking or
stress during pregnancy can affect a child's sexual orientation.

According to the UK
Daily Mail, Dutch neuroscientist Dick Swaab writes in his
book We Are Our Brains: “Although it's frequently assumed
that development after birth also importantly affects our sexual
orientation, there's no proof of this whatsoever.”

“Children brought up by lesbians
aren't more likely to be homosexual. Nor is there any evidence at
all for the misconception that homosexuality is a 'lifestyle
choice.'”

Swaab, who is based at the University
of Amsterdam, claims that the lifestyle of expectant mothers affects
the sexuality of their unborn baby. Factors Swaab cites include
smoking, taking drugs or stress during pregnancy.

“Pregnant women suffering stress are
also more likely to give birth to homosexual children, because their
raised levels of the stress hormone cortisol affects the production
of fetal sex hormones,” Swaab wrote.